Intermittent film feed for motion picture projectors



July 30, 1940 E. VOLLENWEIDER 2.209588 INTERMITTENT FILM FEED FOR MOTIONPICTURE PROJECTORS Original Filed March 15, 1937 2 Sheets-Sheet l I I II I l INVEN TOR. f/m/ V0//enn e/ae/- July 30, 1940. E. VOLLENWEIDERINTERMITTENT FILM FEED FOR MOTION PICTURE PROJECT Original Filed March15, 1937 2 Sheets-Sheet 2 INVENTOR Patented July 30, 1940 UNITED STATESPATENT OFFICE INTERMITTENT FILM FEED FOR IVIOTION PICTURE PROJECTORSEmil Vollenweider, Sacramento, Calif.

1 Claim.

This invention relates generally to a motion picture projector; theinvention being directed particularly to an intermittent film feedmechanism. The present application is a division of my copendingapplication for U. S. patent on Motion picture projector, Serial No.131,030, filed March 15, 1937.

The principal object of this invention is to provide an intermittentfilm feed or shuttle mechanism for motion picture projectors and whichmechanism is arranged to feed the film through the film gate at properspeed without distortion or buckling and without undue wear on the filmas now occurs in some projectors particularly those intended for homeuse or the like and which projectors usually are constructed to receivea relatively narrow film.

Another object of my invention is to provide an intermittent film feedmechanism which is so 20 designed that it is readily adaptable for usein connection with motion picture projectors of the double projectiontype; that is, a projector in which either 8 mm. or 16 mm. film may beused selectively. A further object of the invention is 25 to produce asimple and inexpensive device and yet one which will be exceedinglyeffective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relativearrangement of parts as 30 will fully appear by a perusal of thefollowing specification and claim.

In the drawings similar characters of reference indicate correspondingparts in the several views:

35 Figure l is a fragmentary side outline of a motion picture projectorillustrating generally the position of the intermittent film feed orshuttle mechanism on the projector and relative to the film gate.

40 Figure 2 is an enlarged side elevation of the shuttle mechanism withthe film claws in retracted position.

Figure 3 is a similar view but with the film claws raised but notmaterially advanced.

45 Figure 4 is an enlarged sectional plan view of the shuttle mechanismshown in connection with the film gate, and taken on line 4 l of Fig. 2.

Figure 5 is an enlarged cross section on line 5-5 of Fig. 3.

50 Referring now more particularly to the characters of reference on thedrawings, the projector upon which my improved intermittent film feedmechanism is shown in the present instance comprises a body I having aventilated 55 casing 22 projecting laterally from one side and enclosingthe usual source of light and provided with a condenser lens 3. Arms 4are mounted on and diverge forwardly from the body and at their outerends carry the spindles for removable film supply and take-up reels 5driven in the usual 5 manner. An adjustable dual film gate unit com--prising a vertical 16 mm. gate and a. parallel 8 mm. gate 6a disposedahead thereof, is mounted on and projects laterally from the side of thebody between the condenser lens 3 and a pro 10'- jecting lens I mountedon the side of the body some distance ahead of the lens 3. Upper andlower film feed sprockets 8 are mounted on the side of the body in theusual position, such V sprockets being duplicates, the lower one beingdisposed in an inverted position relative to the upper sprocket. Thedual film gate is constructed according to the disclosure thereof in theabove identified copending application Serial No. 131,030 while thesprocket film feed is constructed in the manner shown and described inmy copending divisional application for patent entitled Sprocket filmfeed for motion picture proiectors, Serial No. 166,096, filed September28, 1937.

The intermittent film feed or shuttle mechanism which is the subjectmatter to which the present application is particularly directedcomprises the following:

A shuttle arm 9 is pivoted on a spring tension bolt l0 threaded into asupporting block 13 disposed against one side of body I, a spacingwasher H maintaining the arm free from the block for pivotal movement.The arm 9 is horizontally slotted as at 52 in order that said arm maynot only swing about the bolt as an axis but may also slide radiallyrelative thereto. The arm 9 extends rearwardly from bolt l0 alongsidethe film gates 6 and 6a and is formed at its rear end with a laterallyprojecting finger l3 having spaced forwardly extending film engagingclaws M. This finger I3 is disposed to the rear of the film gate 6 andthe claws 14 extend through vertical slots S in the back of film. gate 6whereby the claws may project therethrough and engage in the usualopenings in the 16 mm. film in said gate. Another finger I5 projectslaterally from the shuttle arm 9 intermediate the two film gates, thisfinger being provided with a film engaging claw IB which is arranged toengage the 8 mm. film in gate 6a through vertical slot S The supportingplate ll for the film gates is also vertically slotted to permit ofunrestricted up and down motion of the finger 15. As the claw I6 isdisposed closer to the pivotal axis of arm 9 than claws I4, claw IE willmove a lesser distance than claws l4. Thus, by proper spacing of theclaws the same intermittent film feed or shuttle mechanism may be usedfor both 16 mm. and 8 mm..film, the latter of course requiring lessmovement per frame.

A shaft l8, driven and properly timed as usual, extends through block Band a circular cam I9 is eccentrically mounted on the end thereof, saidcam riding in and engaging the wall of a vertically disposed oblong slot20 cut through shuttle arm 9. Another eccentric cam 2|, of substantiallytriangular configuration is mounted on shaft l8 and engages withinturned flanges 22 on the upper and lower edges of the shuttle arm 9.

The cams l9 and 2| are so arranged that, with the rotation of the shaft18, the shuttle arm 9 will be moved so that the claws I4 and 16 willalternately travel in a true vertical plane and then in a truehorizontal plane; the claws on the upward stroke being retracted andfree of the film and advanced in a film engaging and moving position onthe downward stroke. Each alternate rectilinear motion of the claws inboth vertical and horizontal plane is accomplished only by an exactingbalance between the cams, the circular cam functioning to compensate forthe arcuate motion which would otherwise be imparted to the claws I4 andIt as the triangular cam raises or lowers arm 9, while the triangularcam functions tocompen sate for the deflection from a horizontal planewhich would otherwise occur as the circular cam advances or retracts theclaws.

As the claws I and it move With a rectilinear motion both vertically andhorizontally, they out distortion of buckling and they also retract fromor advance into the film without binding. My improved shuttle mechanismaflords an effective and silent means to impart intermittent movement tothe film smoothly and without wear on the same.

From the foregoing description it will be readily seen that I haveproduced such a device as substantially fulfills the objects of theinvention as set forth herein.

While this specification sets forth-in detail the present and preferredconstruction of the device, still in practice such deviations from suchdetails may be resorted to as do not form a departure from the spirit ofthe invention, as defined by the appended claim.

Having thus described my invention, what I claim as new and useful anddesire to secure by Letters Patent is:

In a motion picture projector having a condenser lens and a pair of filmgates for difierent sized films spaced ahead of the lens, the gatefarthest from the lens being adapted toreceive the smallest film, ashuttle arm projecting ahead of the gates, film engaging claws on thearm spaced according to the spacing of the gates and adapted to engagefilm therein, means pivotally mounting the arm at a point ahead of theclaws for oscillating movement in a vertical plane whereby with movementof the armthrough a predetermined number of degrees the claws will movethrough paths of different lengths, and means to actuate the arm.

EMIL VOLLENWEIDER.

move the film down through the film gates with-

